It seemed to become an epidemic throughout the country. A high-profile case occurred, and the police, over eager to please the media and the public, would get information diarrhea.
"We are talking to a person of interest...." you would always hear, and then they would sometimes actually go on to discuss who the person was. But sometimes, they didn't have to. Once the news media realized that they were onto possible suspects, they camped outside the police station and followed detectives as they went out to follow leads. Next thing you know, Ashleigh Banfield (remember her?) would be broadcasting live from the front stoop of some neighbor's house, interviewing some little old lady about her next door neighbor, and "what exactly did the police ask you, Mrs. Farnsworth?"
This is bad because the more information you send out into the public atmosphere, the greater the potential is for misinformation to be exhaled right back at you. Go public that the subject injured his foot when he left the crime scene, and you'll have a thousand jilted girlfriends calling about how their boyfriend came limping into the house that night.
Remember the Beltway Sniper shootings of 2002, which terrorized the Baltimore/D.C. area? Police officials couldn't shut up about what they were doing, who they were talking to, and what houses they were serving search warrants on. It got ridiculous. In jurisdictions where you have elected Sheriffs, this kind of irresponsible media relations means only one thing: they were competing for free air time.
The public has a "right to know" up until the point where knowing causes problems for investigators and prosecutors. Of what value is it to tell the public that you are investigating Ed Humphrey? In Gainesville's case, it served nothing but to show that their administration was wreckless, willing to damage an innocent man's reputation, and ---completely wrong.
When they did announce that they had the right guy--Danny Rolling--they were looked at like the agency that cried "wolf."
Now, we have a recent very high profile case in Chicago, in which it took the prosecutor's office almost a year to make a decision to charge. Consequently, they didn't release the video of the shooting, prompting deafening cries of "Coverup!"
I don't know all the details; I have to be honest and say that I've been too busy to really read everything about the case, but on it's face, I can tell you this: a video of the shooting is called "evidence" and you don't release evidence before you charge someone--in fact it shouldn't even be released before the trial. You're not supposed to taint the public (from which your jury is chosen) and besides, whatever is in the video has to be released to the defense during discovery, so no one gets to "coverup" anything. If you stray from that policy, you then create a precedent. I don't think the local prosecutors in Illinois, or anyone else, can afford to reshape their policy so that every public outcry forces them to reveal the evidence they have in a criminal case. I'm not saying they did everything right (there is a lot of discussion about many mistakes--or deliberate acts--they might be responsible for), I'm just saying that even if they did everything in good faith, they would be vilified for not releasing the video.
In a case like Chicago, the public is already deeply tainted by seeing the video. What if the video had shown that the officer had been clearly justified, and that the shooting victim, in this case or any other, had provoked an action of self-defense on the part of the officer. Then, my friends, the public outcry would be "you're trying to taint the public so the officer gets off!!"
Because of recent events nationwide, and the behavior of police departments all the way back to Gainesville, this will forever be a "no-win" situation.